Lymphoscintigrams were performed using technetium-99m antimony sulfur colloid in 21 patients with cutaneous malignant melanoma. Scintigraphic results were concordant with clinical prediction of lymph drainage in six of 11 patients with trunk melanoma, in five of seven patients with extremity lesions, and in none of three patients with scalp melanoma. Thirteen patients showed activity in more than one regional node group. Eleven patients had focal activity in areas other than regional node groups (i.e., in-transit or central lymph nodes). Lymphadenectomy was performed in 19 patients. In each case, the regional lymph node area chosen for resection was positive scintigraphically. The presence of 99mTc activity in excised lymph nodes was documented by scintillation counting and autoradiography. Metastatic disease was found in the resected nodes of 12 patients. Lymphoscintigraphy may be useful in planning lymphadenectomy in some patients with cutaneous melanoma.